Technical Field
The present disclosure relates to a screening apparatus and a screening method for illuminating microparticle, such as cells, detecting a microparticle to be a target sample based on fluorescence emitted from the microparticle, and selectively sucking and collecting the relevant microparticle.
Background Art
In the related art, microparticle screening apparatuses are widely used as apparatuses for identifying and sorting microscopic samples, such as cells, in research and testing in the medical field. Recently, in research and testing organizations, there is a need for obtaining identifying and sorting processes of the samples without fracture and for increasing efficiency of research and testing by performing those processes more accurately. Particularly, in a certain field, due to an increasing need for performing the identifying and sorting on a cell-by-cell basis, there is also a need for increasing accuracy and efficiency in the identifying and sorting processes on a cell-by-cell basis.
FIG. 21 is a schematic diagram showing a culture chamber of the related art for culturing cells used as samples. A culture chamber 400 has a two layered structure including a cell culture room 401 disposed at an upper layer and a warm water circulation room 402 disposed at a lower layer.
At the cell culture room 401, which is disposed at an upper layer, a cover glass 403 for culturing cells M′ is secured to a cover glass securing unit 404 and a closed space 405 is formed between the cover glass 403 and an optical glass, described below, of the warm water circulation room 402. The cover glass securing unit 404 is provided with culture liquid changing ports 406 through which a cell culture liquid in the second closed space 405 can be changed.
At the warm water circulation room 402, which is disposed at a lower layer, two pieces of optical glass 407, 407 are disposed to oppose each other and secured to an optical glass securing unit 408. Between these two pieces of optical glass, a closed region 409 for circulating warm water is formed. Further, the optical glass securing unit 408 is provided with a warm water inlet 410 through which warm water flows into the closed region 409 and a warm water outlet 411 through which warm water flows out from the closed region 409.
With the culture chamber of the related art, a culture liquid in the closed region 405 can be changed through the culture liquid changing ports 406, and the temperature of the culture liquid can be controlled by performing PID control of the temperature of warm water in the warm water circulation room 402 in accordance with the measured temperature of the culture liquid in the closed region 405 (e.g., see Japanese Patent No. 4117341).
FIG. 22 is a cross sectional view showing another culture vessel of the related art. A culture vessel 500 is adhered and secured to a substrate 502 with adhesive seal 501 such as silicon seal. A culture liquid is accumulated in a liquid exchange unit 500A of the culture vessel 500 through a tube 503. The new culture liquid accumulated in the liquid exchange unit 500A is changed with the old culture liquid in the cell culture section 504 through a semipermeable membrane 505, and the old culture liquid is drawn out through a tube 506. With this configuration, it is also possible to change the culture liquid in the culture vessel 500 and in the cell culture section 504 through the tubes 503 and 506 (e.g., see Japanese Patent No. 4002720).
FIG. 23 is a drawing showing yet another culture vessel of the related art. A chamber 601 in which a culture vessel 600 is accommodated is provided with two glass tubes 602 and 603. Each of the glass tubes 602 and 603 penetrates through a side wall of the chamber 601 and is fixed to the chamber 601. One end of each of the glass tubes 602 and 603 is immersed into a culture medium in the culture vessel 600.
When giving a drug stimulus to culture cells in the culture vessel 600, the user makes use of a pipette 604 (or a syringe) to discharge the culture medium through the glass tube 603 and immediately after this, a drug is injected into the glass tube 602. A dosage sensor 605 comprising a pressure sensor is attached to a surface of the glass tube 602, and as the drug passes through the glass tube 602, a signal in response to timing of the passage is transmitted to a computer 605.
With this configuration, the culture medium in the culture vessel 600 can be discharged through the glass tube 603 and a drug can be injected into the culture vessel 600 through the glass tube 602. Also, with the dosage sensor 605, presence or absence of dosing or timing of dosing can be monitored (e.g., see Japanese Laid-Open Patent Publication No. 2008-136415).
However, with the culture chamber of the related art shown in FIG. 21, when replacing a culture medium in the closed region with a new culture medium, a new culture medium mixes with an old culture medium and thus a new culture medium and an old culture medium cannot be accurately replaced. With the culture vessel shown of the related art in FIG. 22, since an old culture medium in the cell culture section 404 is replaced with a new culture medium through the semipermeable membrane 405, similarly to the technique of FIG. 21, a new culture medium and an old culture medium cannot be accurately replaced and a long time is required for replacement.
Further, with the culture vessel of the related art shown in FIG. 23, since a culture medium is discharged from a culture vessel, and immediately after, a drug is injected into the culture vessel using a pipette or a syringe, it is not possible to replace the culture medium and the drug accurately, and also, it is inefficient.
Particularly, in a case where a reagent is introduced into one of the culture chambers or the culture vessels described above, the reagent will be diluted due to the mixing of the reagent and the culture medium in the vessel. When it is attempted to perform sorting using as little reagent as possible for saving resources and costs, there is a problem that an emission intensity of the target sample becomes weak, and sorting accuracy decreases.
The present disclosure is related to providing a screening apparatus and a screening method that can accurately and efficiently replace a liquid in a vessel retaining microparticles, and can improve sorting accuracy.